Tech Tips: Timing Is Everything

Timing and therefore timers are integral to many electronic security and door control applications. Timing functions can be included with a product, or may be a discrete module when you are assembling a system out of component parts.

We used to have to design and build our own timer modules before they started being offered as auxiliary modules and designed and built into access controls, locks, switches and power supplies.

Here is a description and brief explanation for some common types of timers

DELAY ON TIMERS: Delay on timers were originally used to provide alarm system owners a time window to leave a premises after arming their alarm system or a time window to deactivate the alarm when entering the premises where the alarm system is armed. Entry and Exit Delays and followers are all part of alarm systems 101.

Another application is when using low energy door operators in conjunction with electric locking devices. If a door operator tries to open a locked door, one of two things is likely to happen:

1. The safety sensors built into the door operator will interpret the resistance to opening caused by the lock as an obstruction and respond accordingly, or

2.The door operator will put opening pressure on the door and ‘load’ down the electric lock’s latch, causing it to bind and not release. Use a DELAY ON timer so that when the door operator is triggered, first the electric lock is unlocked and then after a brief delay, the door operator is actuated.

DELAY OFF TIMERS: Delay off timers were once used on alarm systems too as bell cutoffs. Once the alarm system was set off, the timer would shut off the local alarm siren or bell after a preset period of time rather than allow the bell or siren to sound until a person with the authority to disarm the system showed up.

We use delay off timers in door controls so when a REX button is pressed, the electric lock will remain unlocked for longer than the button is depressed. This timed unlock is a code requirement for door control systems.

DELAYED EGRESS TIMERS: This is described as a special locking arrangement and these locks have very specific requirements depending upon the structure or door the delayed egress is used on and the building code that is enforced in the jurisdiction or the AHJ (Authority Having Jurisdiction) doing the inspection of the premises.

PULSING TIMERS: We use these for visual and audible annunciators for warnings and alarms. Pulsing lights and sounds are very irritating and demand attention. Strobe lights and pulsating audible signals are available, or you can use a timer module with a pulsing function if your application warrants it.

PNEUMATIC TIMERS: Amazing! A timer that does not use electric power. These are especially useful for retrofitting to existing door control systems where the original wiring does not provide enough electrical conductors to support an electronic timer module. Sometimes someone will point out that a pneumatic timer will continue to operate in the absence of electrical power, but since most electric locking devices will not operate without power, who cares?

MULTI-FUNCTION TIMER MODULES: Now we’re getting somewhere. These sophisticated timer modules allow the creative system designer to come up with an enhanced feature. Example would be a door unlock timer which automatically relocks when the controlled door recloses after an entry or an egress. These are sometimes referred to anti-piggyback or anti-passback.

REAL TIMER CLOCK CONTROLLERS: These have clocks built into them so you can program locking, and unlocking schedules based on the time of day or the date depending on the features offered by the particular timer.

TIMERS BUILT INTO OTHER PRODUCTS: These days we use products which have functions and features built into the product, making them easier to deploy and not requiring interconnecting wiring or protective enclosures.

Protective enclosures provide resistance to tampering, vandalism and rodents, and might be required by electrical code. Enclosures also make for a more professional looking installation, and may allow you to locate equipment in a more accessible location rather than high on a wall, in a locked room or above a dropped ceiling which make end-user access and possible subsequent service calls (by you later on) less convenient.

Alarm Controls

The Alarm Controls MT-1 Mini timer is encapsulated for moisture protection. This device can be located in a door frame or inside a wall without worries of moisture or other contaminates affecting its operation.

Normal Operation: A momentary or maintained closure of the black and orange leads will cause the relay contacts to transfer and remain closed until the delay period ends. At the end of the delay period the relay contacts will return to their original state. Closure of the black and orange leads during the delay period will cause the timer to re-start.

Fail safe operation: Relay is energized when power is applied. During timing mode relay is not energized.

Features / Specifications:

Voltage range: 12 to 24VAC or VDC
Current Draw: 37mA (maximum)
Relay operating mode: one shot
Contact arrangement: S.P.D.T.
Contact rating: 2 Amps @ 35VDC or 125VAC
Time setting: adjustable from 2 to 45 seconds
Temperature rating: -25˚C to +70˚C
Size: 1-3/4" x 1-3/4"
Mounting: adhesive foam tape

For delayed egress applications, Alarm Controls offers the Models DE-1 and DE-1 1SEC delayed egress station. This micro-controller based unit will provide an effective means of locking an exit door while still providing egress during an emergency.

Pushing the square green button on the unit will start the irrevocable exit time. On the DE-1, a two-second nuisance feature requires the button to be pushed and held before the timer will start. At this time, the alarm relay will be energized and the sounder and light will turn on. The DE-1 1SEC does not have a nuisance feature.

At the end of the adjustable time delay (2 to 30 seconds), the lock relay is energized, allowing the exit door to un-lock. The alarm relay, lock relay, sounder and light will remain on until reset with the keyswitch.

To enable the optional reset feature, cut the leads to the keyswitch and tie the leads together electrically. Once this feature is enabled, the lock relay will be de-energized after a time delay equal to the setting of the adjustable time delay (2 to 30 seconds) thereby allowing the door to re-lock.

Specifications:

Input Voltage: 12 to 24 VDC
Current Draw: 200 mA maximum
Delay Time: 2 to 30 seconds adjustable
Nuisance time delay (DE-1 only): 2 seconds
Outputs: SPDT Alarm Relay and Lock Relay
Contact Rating: 5 A @ 35 Volts
Buzzer Sound Level: 85 dB @ 3 feet
Buzzer Frequency: 2900 Hz
Button Illumination: LED

Alarm Controls’ Model TS-14 pneumatic pushbutton switch is used for REX and other door release applications, and is effective where you only have a pair of conductors available to the switch location, and where the ambient temperature is relatively moderate.

Features:

No external power required
Pneumatic time delay with 1-1/2" mushroom button
One normally-open contact pair and one normally-closed contact pair
Contacts rated 10A @ 35VDC
Time range settable between 2 and 60 seconds
Switch time is repeatable ± 10%
Switch mounted on a single gang stainless steel electrical plate
UL listed components
Temperature range +15F to +120F
Switch depth 2-1/4" behind plate
Specify the color of the pushbutton (Red or Green); and satin Stainless Steel plate is also available.

More Info: www.alarmcontrols.com

Altronix

The ALTRONIX AT4 Timer provides 365-day, 24-hour annual event, 4 Channel, Alphanumeric LCD Display and Battery Charger, inside a BC200 Enclosure. This ALTRONIX product answers the call for a timer which can be installed in less than ideal environments which is self-contained, has a traditional non smartphone/computer user interface and offers multiple outputs and programming options for many applications.

The AT4 is extremely versatile, designed to support a wide range of applications: Home and Building Automation, Security, Access Control, Lighting Control, etc.

Input: 12 to 24 volts AC or DC operation.

Standby current: 20mA with relays off combined with 40mA for each relay on.

Four (4) Form "C" relay contacts are rated 10A @ 120VAC/28VDC.

Each relay operates independently.

It can accommodate 254 individually programmed daily/weekly events. Block programming capacity can accommodate a total of 1778 events per week. 254 programmable holiday events are available.

Features:

EE Prom memory protects against loss of programming due to power failure.
Clock synchronization 60Hz (AC operation).
Accurate crystal controlled clock (DC operation).
"First man in" option.
Standard or Daylight Savings Time settings.
Automatic compensation for leap year.
Battery Backup
Built-in charger for 12VDC sealed lead acid or gel type batteries (Max. charge current 300mA).
Lithium battery backup maintains clock. Order Altronix part # LB2032.
Alphanumeric LCD display simplifies programming.
Operating Temperature -20ºC to 49ºC (-4ºF to 120ºF).
Storage -25ºC to 70ºC (-13ºF to 158ºF).
Relative Humidity 85% +/- 5%.

The Altronix PT724A 24 Hour 365 Day Event Timers are equipped with an independently controlled form "C" relay contact that provides many latching and/or momentary operations during a program schedule of your choice. Events may be set for single or multiple operations on a daily and/or weekly schedule.

Input 12 to 24 volts AC or DC operation

Relay Form "C" relay contacts are rated 10A @120VAC/28VDC.

Standby current: 10mA (relay off) 50mA (relay on).

Features:

EE Prom memory protects against loss of programming due to power failure.
Accurate crystal controlled clock.
50 individually programmed daily/weekly events.
Block programming capacity can accommodate a total of 350 events per week.
10 programmable Holiday dates.
"First man in" option.
Standard or Daylight Savings Time settings.
Automatic compensation for leap year.
Visual Indicators
Alphanumeric LCD display simplifies programming.
Battery Backup
Built-in charger for 12VDC sealed lead acid or gel type batteries(Max charge current 100mA).
Optional lithium battery backup maintains clock.
Operating Temperature -20ºC to 49ºC ( -4ºF to 120ºF).
Storage -25ºC to 70ºC ( -13ºF to 158ºF).
Relative Humidity 85% +/- 5%.

More Info: www.altronix.com

SECURITRON iMXDA

Securitron’s Integrated Movement Exit Delay with Advanced Technology offers the installer a complete delayed egress and access control solution built into an integrated device. The unit has the flexibility to be adapted to many installation configurations and can be configured to comply for various building codes. Of course it is highly recommended to verify that the AHJ will approve your application and this product before going to contract on a project. Special locking arrangements require more planning and preparation since they will affect the life safety characteristics of the opening.

iMXDa helps prevent peril to persons/patients and property loss/theft for businesses. Applications include dementia wards, hospitals, dormitories, airports, child care facilities and retail or warehouse environments.

Installation requires no alteration or replacement of existing fire-rated or non-fire-rated latching hardware. False triggering is eliminated by up to 1" of authorized door movement.

Product Features:

1200 lbs. holding force Magnalock
New shorter 12.5" overall length will fit most any door with a closer installed
Automatic dual voltage - no field adjustment required
New bracket-mounted design improves strength and installation time
Microprocessor monitored BondSTAT magnetic bond sensor (MBS) and integrated door position switch (DPS) standard
Reverse action plunger allows for adjustable alarm initiate gap from 1/8" [3.2mm] to 1" [25mm]
Bright LEDs indicate unit status from the secure side of the door

DIP switch selectable options:

Nuisance alarm times - 0 to 3 seconds
Irrevocable delay times - 15 or 30 seconds - user selectable
External bypass delay times - 0, 5, 10 or 15 seconds
Post alarm reminder - user selectable
Bypass expiration alarm - user selectable
Manual relock or delayed automatic relock (BOCA) - user selectable
External alarm relay isolated dry contact (1A at 24VDC)
External reset
iEXD version allows alarm initiation via an external panic device

The SECURITRON EEB emergency exit button is a redundant backup that ensures safe egress. Install the EEB Emergency Exit Button next to the door to provide additional safety and redundancy as required by code when using a motion detector for a request-to-exit device.

Emergency Exit Buttons offer additional safety, as required by code, for possible malfunction of motion exit sensor. They are mounted next to the door. Momentarily pressing the button releases door for 30 seconds

Features include: